Laser energy has been used for treatment in medicine and surgery for many years. In order to deliver laser energy to the tissue to be treated, various types of laser beam delivery systems have been developed including systems incorporating laser energy waveguides at the distal ends thereof.
With these laser beam delivery systems, different tissue treating effects have been achieved by using differently sized and shaped waveguides to produce varied laser energy output distributions.
The most common such delivery systems include either a waveguide including a cone or pointed tip for delivering a concentrated, high energy beam of laser energy to a defined and concentrated tissue site or, alternatively, a circularly, spherically or cylindrically curved waveguide for delivering laser energy in a circular, spherical or cylindrical pattern to a region of selected tissue.
A disadvantage of the instrument including a pointed waveguide is that, although suitable for directing a concentrated high energy beam of laser energy to a defined tissue site to effect, for example, a cut, such instrument is not suitable for the efficient and cost effective treatment of a relatively larger tissue region.
Another disadvantage of emitting laser energy from the distal pointed or coned tip of an optical waveguide is the small "spot" size on tissue and the rapid divergence of the laser beam as the waveguide is moved away from the tissue.
The instrument including a circularly, spherically or cylindrically curved waveguide, although able to deliver energy to a region of tissue, is disadvantageous because it does so in a random or uneven pattern which results in some tissue being overexposed to the incident energy and some being underexposed. Round "spot" emissions make it difficult to produce an even exposure without the overlapping of energy exposures.
Thus, there continues to be a need for a surgical laser instrument which allows for a controlled and cost effective treatment of a rectangular tissue region, e.g., for dermatology, tonsillectomy, and the like treatments and, more particularly, for a surgical laser instrument which allows a surgeon to evenly sweep or "paint" a large tissue area at a desired energy level.